Not to go completely geek on you people on this unlikely topic, but..
shewolfnm wrote:If you press in at the base of the shaft just above the scrotum, and measure from THAT point ( wich is the true end of the penis) you can almost always add 2 inches.
If you only measure what you can see ( and essentially feel) then yeah.. that mans got a 6 incher at best..
The Q & A on the erectionphotos site says:
"Length is measured along the upper side of the erect penis, usually with a ruler but sometimes with a flexible tape. The length is from the tip end of the penis to the pubo-penile skin junction, which is the point where the penis joins the abdomen."
The Wikipedia page says:
"Length of a penis is typically measured with the subject standing and the penis held parallel to the floor. Measurement of length goes horizontally along the top of the penis from the patient's base to the tip."
The Penis Size Debate site says:
"When the penis is in full erection, push it down until it is at a straight angle with the body. Measure along the top from the base until the tip. Some people argue over whether you should press the ruler as far as possible against the pubic bone (bone-pressed) or just hold it loosely against the skin where the penis meats the body. The argument rises from the fact that overweight people lose a lot of length due to fat build-up at the pubic bone. Pressing inside with a ruler might give them a truer measurement although during intercourse they will not be able to use that extra inch or two. The fairest way of measuring is probably to hold the ruler firmly against the body without forcing down on it."
flushd wrote:Didn't know that different ethnicities had different vaginal sizes. Makes sense I guess; but it is still individual eh. Like, how some Asian women have large breasts, or some black women have little booty.

Dunno about women but on "Race and penis size", the Wikipedia page notes that:
"There is considerable debate as to whether specific racial variations in penis size exist, and if they do, whether observed variations can be explained in terms of other factors such as correlations of penis size to body size. In any case, within-group variation in penis size (±30%, see above) seems to be considerably larger than claimed between-group variation of average penis size (±4%, see below)."
So yes, you still stand a fair chance of finding an Asian man with a bigger dick than his black neighbour ;p
There. I think I just set a new record for geekdom.